Lebanese army investigators inspect the scene of an explosion in Beirut, Lebanon, where a car bomb killed a pro-Western politician and at least five other people Friday.

BEIRUT — A powerful car bomb killed a prominent Lebanese politician critical of Syria and its ally Hezbollah, hitting his SUV Friday as it drove through a ritzy business district near Beirut’s waterfront, shredding trees and scattering glass and twisted scraps of metal across the pavement.

Allies of the slain politician, former finance minister Mohammed Chatah, indirectly blamed the Shiite Hezbollah group for the bombing, raising tensions between Lebanon’s two main political camps at a time when the country’s factions are already deeply at odds over the civil war in neighboring Syria.

The morning explosion echoed across Beirut and threw a pillar of black smoke above the city’s skyline. The force of the blast punched a nearly 2-yard-wide crater in the street, set at least three cars on fire and shattered windows in office buildings and apartment towers up to a block away.

The 62-year-old Chatah, who was also a former Lebanese ambassador to the United States and a senior aide to ex-Prime Minister Saad Hariri, was killed along with his driver and four others, the National News Agency reported. The Health Ministry said at least 70 people were wounded.

In a statement, the 15 members of the U.N. Security Council strongly condemned the attack and “reiterated their unequivocal condemnation of any attempt to destabilize Lebanon through political assassinations.”

The bombing deepened the sense of malaise in Lebanon, which is struggling to cope with the fallout from the civil war in Syria, including the influx of more than 1 million Syrians who have sought refuge from the violence in their homeland.

Lebanon also has had only a weak and ineffectual caretaker government since April, with the two main political blocs unable or unwilling to reach a compromise to form a new Cabinet.

Hariri, a Sunni politician, heads the main, Western-backed coalition in Lebanon, known as the March 14 alliance. Hezbollah, which enjoys the support of Syria and Iran and commands a militia stronger than the national military, leads those on the other side of Lebanon’s political divide.

There was no immediate claim of responsibility for Friday’s attack, but the bombing was reminiscent of a string of assassinations of around a dozen members of the anti-Syrian Hariri camp that shook Lebanon between 2004 and 2008.

The most dramatic of those was the massive suicide bombing in 2005 in downtown Beirut — some four blocks from the site of the explosion — that killed Hariri’s father, Rafik, also a former prime minister. Hariri’s allies accused Syria of being behind the killings, a claim Damascus denied.

The opening session in the Hariri assassination trial is due to be held in less than three weeks in The Hague, Netherlands, where the U.N.-backed tribunal investigating his killing is based. Five Hezbollah members have been indicted for their alleged involvement in the assassination. Hezbollah rejects the accusations, and has refused to hand the men over.

Saad Hariri said in a statement that “the ones who are running away from international justice and refusing to appear before the international tribunal” were behind Chatah’s assassination.

Hariri said those responsible are “the same ones who are opening the doors of evil and chaos into Lebanon” and “brought regional fires to our country,” in a clear reference to Hezbollah’s armed intervention in support of Syrian President Bashar Assad.

The Shiite group’s overt role in Syria has inflamed Lebanon’s already simmering sectarian tensions. A wave of violence that has washed across the country this year has fueled predictions that Lebanon, which is still recovering from its own 15-year civil war that ended in 1990, is on the brink of slipping back into full-blown sectarian conflict.

In recent months, a series of explosions have struck districts dominated by Hezbollah, apparently in retaliation for the group’s decision to dispatch its fighters to Syria, while a deadly twin car bombing hit the northern city of Tripoli, a Sunni stronghold. There have also been repeated clashes between Sunnis — who largely back Syria’s rebels — and Shiites and Alawites who back Assad.

The last major assassination in Lebanon took place Oct. 19, 2012, when a car bomb killed Lebanon’s top intelligence chief, Wissam al-Hassan. Al-Hassan, a member of Hariri’s security circle, was a powerful opponent of Syria’s influence in Lebanon and many here blamed his killing on Syria.